This invention is a general method for forming force sensing devices with multiple isolated channels in which two or more materials (solid, liquid or gas) can be isolated one from another. These devices have various attributes that result from this technology that can produce such devices that are either straight or cantilevered. The resulting structures, either cantilevered or uncantilevered, can be tapered to a small tip and should allow for the ability to sense surface forces while using one or multiple channels of the structure for another function.
If there was a general method that could allow for the generation of multiple channel force sensing devices with channels, that could be filled with a solid liquid or gas or left empty or both, this would have significant impact in numerous areas of science and technology. They could form probes that could have multiple attributes such as chemical sensors in one channel with gas in another channel, micro vacuum devices with single channels that could suck up materials and air in a second channel to release such materials, unique nanometric thermocouples, micro voltage, micro capacitance, micro inductive, micromagnetic devices depending on electrical isolation or contact at the tip of electrically conducting materials, microlight detectors if the conductors in the channels are covered with photodetecting materials, microlight sources if the channels of conducting material are coated with electroluminescent materials, multiple channel fountain pens, multiple channel tips for multiple electrochemical and/or optical measurements, micro heating elements, stable micro devices for annealing, soldering, cutting, etc., Peltier microcooling devices, microdynamic cavitation bubble forming devices, generating devices with two isolated electrodes with appropriate electrical inputs, etc. In the past, some of these applications were attempted with single channel devices with less than successful results. For example, microthermocouples with force sensing capabilities have been previously described using a tip that is produced with silicon technology that is then combined with coating procedures to effect a point thermocouple or thermoresistor at the tip of a cantileveied structure. Nonetheless, these coating techniques are very susceptible to the destruction of the point contact at the tip when such tips are employed in contact with a sample surface. The newly invented techniques described in this patent avoid such problems and also allow the production of new structures that were not permitted by such previous technology [C. Prater and T. B. Albrecht, Universal Microfabricated Probe for Scanning Probe Microscopes, U.S. Pat. No. 5,166,520] that was based on some sort of combination of etching or coating rather than the forming procedures used and possible in this invention.
There has been no approach that has been used in the past that would allow the production of the structures described in this patent. Thus, both in terms of the methodology that is described and the type of structures and the devices that can be obtained this is a significant invention over the state of prior art.
The invention is a method to produce a type of probe based on multiple channels of isolated materials that can, if so desired, be cantilevered. The structures and the variety of applications that they provide are a result of the ability of these devices to sense surface forces and thus permit the control of these probes at or above specified surfaces in order to accomplish specific applications.